Winder for winding a band of fabric or knitting or the like on a roller, particularly for circular knitting machines

ABSTRACT

A winder for winding a band of fabric or knitting or the like on a roller, particularly for circular knitting machines, comprising a frame which supports a takeup roller and a traction roller, which is supported by the frame and can be actuated with a rotary motion about its own axis with respect to the frame, the traction roller making contact with the takeup roller, with the interposition of the band wound around the takeup roller, the traction roller being arranged so that its axis is above the axis of the takeup roller and can move toward or away from the axis of the takeup roller as the winding diameter of the band on the takeup roller varies, the winder comprising elements for the actuation of the traction roller with a rotary motion about its own axis with a substantially constant actuation torque.

The present invention relates to a winder for winding a band of fabricor knitting or the like on a roller, particularly for circular knittingmachines.

As is known, circular knitting machines are provided generally with aknitting tensioning device that is arranged below the needle cylinder ofthe machine and applies to the manufacture being formed a downwardtraction that is needed in order to ensure the correct forming of themanufacture.

These tensioning devices generally comprise a pair of rollers withmutually parallel and horizontal axes, between which the manufacture,constituted by a flattened tubular body, is caused to pass, and one ofthese two rollers is motorized so as to apply, in cooperation with theother roller, a traction to the manufacture.

Laterally to the motorized roller, on the side opposite to the rollerthat cooperates with it in applying traction to the knitted manufacture,generally there is another roller, which has the function of increasingthe winding angle of the manufacture onto the motorized roller and ofguiding the manufacture toward a takeup roller that is arranged belowthe tensioning device.

The takeup roller is part of a winding device that is arranged below thetensioning device and comprises generally a frame that supports, so thatit can rotate about its own horizontally arranged axis, the takeuproller onto which the manufacture is to be wound.

In some winders the takeup roller is motorized, while in other windersthe takeup roller is supported by the frame so that it can rotate aboutits own axis and is actuated by contact by means of at least onetraction roller, which also is supported by the same frame so that itcan rotate about its own axis, which is arranged parallel to the takeuproller axis. The traction roller can be actuated with a rotary motionabout its own axis with respect to the frame and the takeup rollerrests, with the interposition of the manufacture that winds about it,against the traction roller so that the rotary motion of the tractionroller is transmitted by contact to the takeup roller, causing theprogressive winding of the manufacture thereon.

For obtaining a uniform winding of the manufacture around the takeuproller without the manufacture undergoing unwanted deformations, theforce with which the manufacture is tensioned during winding around thetakeup roller must remain constant. To meet this requirement, twomethods are usually used: a first method, which we will term“constant-speed operation”, and a second method, which we will term“constant-torque operation”.

In winders that use a traction roller, to which the present inventionrelates, constant-speed operation consists in setting a presettransmission ratio between the motorized roller of the tensioning deviceand the traction roller of the winder. By means of this method, eachvariation of the speed of the motorized roller of the tensioning devicecorresponds to an identical variation of the speed of the tractionroller and therefore there are no changes in the tensioning force of themanufacture during its winding. The preset transmission ratio betweenthe motorized roller of the tensioning device and the traction roller ofthe winder can be obtained by means of a mechanical transmission or byusing variable-speed electric motors which can be controlled in acorrelated manner.

In constant-torque operation, the takeup roller is actuated with arotary motion about its own axis with a torque that can vary and with arotation rate that can undergo variations as a function of the type ofknitting that is manufactured and of the diameter of the roll ofknitting being wound around the takeup roller so as to obtain in anycase, at least in theory, a constant tensioning force of the manufactureduring its winding.

Winding devices based on constant-torque operation are described forexample in WO2011/042298 in the name of this same Applicant, whichprovides for limiting the actuation torque transmitted by the tractionroller to the takeup roller, or in Italian patent 1,293,791 in the nameof this same Applicant, which provides for actuating the takeup rollerwith a torque-controlled electric motor that is feedback-controlled bymeans of a transducer system capable of measuring the tension of theknitting at the input of the takeup roller.

Winders based on torque-controlled operation are preferred to windersbased on speed-controlled operation in machines that perform knittingswith variations of the type or quantity of knitting produced, such asfor example in machines with electronic selection, with particularreference to those that transfer knitting from needles to continuousneedles.

Among winders based on torque-controlled operation, winders that use atraction roller to actuate the takeup roller are the easiest to provideand manage.

In winders that use a traction roller to actuate the takeup roller andthat are based on torque-controlled operation, the traction roller isarranged below the takeup roller, which rests thereon with theinterposition of the manufacture, which winds progressively about thetakeup roller. An arrangement of this kind is illustrated in theabove-cited patent application WO2011/042298.

These winders have the drawback of being affected by the weight of theroll of the band of fabric that is wound progressively about the takeuproller. The total weight of the takeup roller and of the manufacturethat winds about it increases progressively, varying the degree ofadhesion of the takeup roller to the traction roller and the resistanceopposed by the takeup roller to the rotary motion transmitted by thetraction roller to the takeup roller. These variations can causevariations of the tensioning force of the manufacture during its windingaround the takeup roller and therefore can alter the uniformity of thewinding of the manufacture around the takeup roller.

The aim of the present invention is to obviate the drawback cited above,providing a winder for winding a band of fabric or knitting or the likearound a roller, particularly for circular knitting machines, with aconstant-torque operation that maintains a substantially constanttension of the band of fabric or knitting during its winding around thetakeup roller so as to obtain a uniform winding, without deformations,of the strip of fabric or knitting or the like.

Within this aim, an object of the invention is to provide a winder inwhich the winding tension of the band of fabric or knitting or the likeis not affected by the amount of knitting or fabric that is wound aroundthe takeup roller.

Another object of the invention is to provide a winder in which it ispossible to vary the tension to which the band of fabric or knitting orthe like is subjected during winding around the takeup roller.

An additional object of the invention is to provide a winder thatensures high precision and reliability in operation.

Another object of the invention is to propose a device that can bemanufactured at competitive costs and is easy to manage.

This aim, as well as these and other objects that will become moreapparent hereinafter, are achieved by a winder for winding a band offabric or knitting or the like around a roller, particularly forcircular knitting machines, comprising a frame which supports, so thatit can rotate about its own horizontally arranged axis, a takeup roller,around which the band of fabric or knitting or the like is to be wound,and at least one traction roller, which is supported so that it canrotate about its own axis, which is arranged parallel to the axis ofsaid takeup roller, by said frame and can be actuated with a rotarymotion about its own axis with respect to said frame; said tractionroller making contact with said takeup roller, with the interposition ofsaid band wound around said takeup roller, for a transmission of therotation of said traction roller to said takeup roller, characterized inthat said traction roller is arranged so that its axis is above the axisof said takeup roller and can move toward or away from the axis of saidtakeup roller as the winding diameter of said band on said takeup rollervaries, means being provided for the actuation of said traction rollerwith a rotary motion about its own axis with a substantially constantactuation torque.

Further characteristics and advantages of the invention will become moreapparent from the description of a preferred but not exclusiveembodiment of the winder according to the invention, illustrated by wayof non-limiting example in the accompanying drawings, wherein:

FIG. 1 is a partially exploded perspective view of the winder accordingto the invention;

FIG. 2 is a perspective view of the winder according to the invention,with the strip of fabric or knitting or the like to be wound omitted;

FIG. 3 is a perspective view of the winder according to the invention,from a different angle than in FIG. 2;

FIG. 4 is a schematic view of the winder according to the invention,illustrating its operation.

With reference to the cited figures, the winder according to theinvention, generally designated by the reference numeral 1, comprises aframe 2 that supports, so that it can rotate about its own axis 3 a,which is arranged horizontally, a takeup roller 3 about which the band 4of fabric or knitting or the like is intended to be wound. The winder 1comprises a traction roller 5 that is supported, so that it can rotateabout its own axis 5 a, which is arranged parallel to the axis 3 a ofthe takeup roller 3, by the frame 2 and can be actuated with a rotarymotion about its own axis 5 a with respect to said frame 2. The tractionroller 5 makes contact with the takeup roller 3, with the interpositionof the band 4 wound about the takeup roller 3, in order to transmit therotation of the traction roller 5 to the takeup roller 3.

According to the invention, the traction roller 5 is arranged so thatits axis 5 a lies above the axis 3 a of the takeup roller 3 and can movetoward or away from the axis 3 a of the takeup roller 3 as the windingdiameter of the band 4 on the takeup roller 3 varies. The winder 1according to the invention comprises means 6 for actuating the tractionroller 5 with a rotary motion about its own axis 5 a with asubstantially constant actuation torque.

More particularly, the frame 2 is composed of a lower profiled element7, which is arranged substantially horizontally and from which twovertical shoulders 8 a, 8 b rise which are mutually connected, at theirupper end, by a horizontal bar 9. If the winder according to theinvention is intended to be fitted on a circular knitting machine, theshoulders 8 a, 8 b can be provided in an upward region with arms 10 a,10 b so as to connect the frame 2 below the needle cylinder of themachine.

In the illustrated embodiment, the frame 2 supports, in proximity to theupper end of the shoulders 8 a, 8 b, a tensioning device 11 of a knowntype, for example a tensioning device of the type described inWO2011/042298, which is composed of three side-by-side rollers 12, 13,14, respectively: a motorized central roller 12, a contact roller 13that is arranged on one side of the central roller 12, and a guidingroller 14 that is arranged on the other side of the central roller 12.The rollers 12, 13, 14 are arranged so that their axes are horizontaland mutually parallel and the band 4 to be wound about the takeup roller3 passes between the contact roller 13 and the central roller 12 to thenpass between the central roller 12 and the guiding roller 14 to reachfinally the takeup roller 3, which is supported by the frame 2 so thatits axis 3 a is arranged in parallel to the axes of the rollers of thetensioning device.

The takeup roller 3 is composed of a cylindrical jacket about which theband 4 is to be wound and which is closed, at its axial ends, byportions of a shaft or coaxial pivots that constitute the axial ends ofthe takeup roller 3. These axial ends of the takeup roller 3 arecoupled, in a rotatable manner, with the interposition of bearings 15,to the shoulders 8 a, 8 b of the frame 2.

The means 6 for actuating the traction roller 5 comprise a rack 16 a, 16b, which is supported, so that it can slide, by the frame 2 along adirection that is perpendicular to the axis 5 a of the traction roller5. The rack 16 a, 16 b meshes with a pinion 17 a, 17 b, which isconnected to the traction roller 5 by means of a unidirectional motiontransmission device 18, which is adapted to render the pinion 17 a, 17 bintegral with the traction roller 5 in rotation about its own axis 5 ain a forward rotation direction, which causes a rotation of the takeuproller 3 in the direction for winding the band 4 about the takeup roller3, and to uncouple the pinion 17 a, 17 b from the traction roller 5 in areturn rotation direction that is opposite to the forward rotationdirection. The rack 16 a, 16 b is actuated with a translational motionalong its axis, at least in the direction of translation that producesthe forward rotation direction of the pinion 17 a, 17 b, with asubstantially constant force.

More particularly, the actuation means 6 of the traction roller 5comprise a rack 16 a, 16 b that meshes with a pinion 17 a, 17 bconnected to the traction roller 5 by means of a correspondingunidirectional motion transmission device 18 for each one of the axialends of the traction roller 5.

Conveniently, each one of the pinions 17 a, 17 b that meshes with thecorresponding rack 16 a, 16 b is fitted coaxially on one of the axialends of the traction roller 5 and the corresponding unidirectionalmotion transmission device 18 is constituted preferably by a freewheeldevice that is interposed between the respective pinion 17 a, 17 b andthe corresponding axial end of the traction roller 5.

Preferably, the arrangement of the takeup roller 3 and of the tractionroller 5 on the frame 2 is such that the axis 3 a of the takeup roller 3and the axis 5 a of the traction roller 5 are arranged on a samevertical plane so that the axis 5 a of the traction roller 5 is arrangedabove the axis 3 a of the takeup roller 3.

With this arrangement, which is the one shown, the racks 16 a, 16 b arearranged so that their axis is vertical and are conveniently guided bythe shoulders 8 a, 8 be along a corresponding vertical direction.

The axial ends of the traction roller 5 are accommodated slidinglywithin vertical guides 21 a, 21 b that are integral with the frame 2.

More particularly, bearings 22 a, 22 b are fitted on the axial ends ofthe traction roller 5, externally with respect to the region occupied bythe pinions 17 a, 17 b, each bearing engaging slidingly within acorresponding vertical guide 21 a, 21 b that is formed in thecorresponding shoulder 8 a, 8 b of the frame 2. In this manner, thetraction roller 5 can slide vertically upward as the amount of band 4wound onto the takeup roller 3 increases.

Each one of the racks 16 a, 16 b is actuated with a translational motionalong its own axis, in the direction of translation that causes theforward rotation direction of the corresponding pinion 17 a, 17 b, bymeans of a spring 23 a, 23 b that is reloaded cyclically by afluid-operated cylinder 24 a, 24 b.

More particularly, for each one of the racks 16 a, 16 b there is a pivot25 that is integral with the rack 16 a, 16 b and is connected to anotherpivot 26 fixed to a plate 27 that is integral with the correspondingshoulder 8 a, 8 b of the frame 2 by means of the spring 23 a, 23 b. Itshould be noted that along the longitudinal extension of each rack 16 a,16 b there are multiple holes 28 for positioning the pivot 25 so as tomake it possible to vary the preloading of the spring 23 a, 23 baccording to the requirements. The spring 23 a, 23 b is arranged so asto contrast the movement of the rack 16 a, 16 b upward, i.e., cause themovement of the rack 16 a, 16 b downward with respect to the frame 2.The fluid-operated cylinder 24 a, 24 b is connected with its body to thecorresponding shoulder 8 a, 8 b of the frame 2 and operates with thestem of its piston on an end of the corresponding rack 16 a, 16 b.Essentially, the actuation of the fluid-operated cylinder 24 a, 24 bcauses the upward movement of the rack 16 a, 16 b and the loading of thespring 23 a, 23 b, whereas the discharge, i.e., the deactivation, of thefluid-operated cylinder 24 a, 24 b causes the downward movement of therack 16 a, 16 b by the action of the spring 23 a, 23 b. The downwardmovement of the rack 16 a, 16 b, as a consequence of the coupling thatexists between the rack 16 a, 16 b and the corresponding pinion 17 a, 17b, turns the pinion 17 a, 17 b in the forward rotation direction, whichcauses the rotation of the traction roller 5 and consequently, bycontact, the rotation of the takeup roller 3 in the winding direction20, whereas the upward movement of the rack 16 a, 16 b causes norotation of the traction roller 5, since the pinion 17 a, 17 b rotatesin the return rotation direction, which, as a consequence of thepresence of the freewheel device 18, transmits no rotation to thetraction roller 5 and therefore to the takeup roller 3.

Essentially, the force that generates the actuation torque that istransmitted by the traction roller 5 to the takeup roller 3 is the forceproduced by the elastic reaction of the spring 23 a, 23 b that is loadedcyclically by the fluid-operated cylinder 24 a, 24 b. By limitingappropriately the stroke of the fluid-operated cylinder 24 a, 24 b andconsequently the elongation of the spring 23 a, 23 b during loading, theforce generated by the spring 23 a, 23 b and transmitted, by means ofthe coupling that exists between the rack 16 a, 16 b and the pinion 17a, 17 b and by means of the unidirectional motion transmission device18, to the traction roller 5 is substantially constant and thereforegenerates a substantially constant actuation torque of the tractionroller 5.

Consequently, the force that is transmitted by the traction roller 5 tothe takeup roller 3 is also substantially constant, thus achieving asubstantially constant tensioning of the band 4 during its windingaround the takeup roller 3. In practice, the tension T to which the band4 is subjected during its winding about the takeup roller 3 is expressedby the formula (see FIG. 4):

T=F _(t) =C _(t) /R _(t) =F _(m) ·R _(p) /R _(t)

As explained above, by a reduction in the extent of the movement of therack 16 a, 16 b by means of the action of the fluid-operated cylinder 24a, 24 b, the tension T remains substantially constant.

By means of the movement of the fixing point of the pivot 25 along therack 16 a, 16 b it is possible to vary the preloading of the spring 23a, 23 b and consequently to vary the tension that bears on the band 4during winding around the takeup roller 3.

As an alternative, instead of a helical spring 23 a, 23 b, as shown, itis possible to use a pneumatic spring that can be included in thefluid-operated cylinder that can be actuated cyclically in order toreload the pneumatic spring. In this case it is possible to vary thewinding tension of the band 4 by adjusting the force generated by thepneumatic spring.

As a further alternative, each rack 16 a, 16 b can be actuated with analternating translational motion along its own axis by means of adouble-acting fluid-operated cylinder. In this case it is possible tovary the winding tension of the band 4 by varying the supply pressure ofthe double-acting fluid-operated cylinder.

For the sake of completeness in description, it should be noted that theframe 2 can also be supported by means of a lower supporting element 29that supports the frame 2 so that it can rotate about a vertical centralaxis which, in the installation of the device on the knitting machine,is arranged at the axis of the needle cylinder in order to allow theframe 2 to rotate together with the needle cylinder of the knittingmachine.

Operation of the device according to the invention is as follows.

At the beginning of the winding of the band 4 around the takeup roller3, the traction roller 5 is proximate to the lower end of the verticalguides 21 a, 21 b, as shown in FIGS. 2 and 3. The band 4 of fabric orknitting or the like, which arrives from the tensioning device 11, iswound with an initial portion around the takeup roller 3 and theactuation of the traction roller 5 with a rotary motion about its ownaxis 5 a produces by contact the rotation of the takeup roller 3 aboutits own axis 3 a and therefore the progressive winding of the band 4that originates from the tensioning device 11 about it. As explainedabove, the traction roller 5 is actuated by means of the alternatingmovement of the racks 16 a, 16 b along their own axis, i.e., in theillustrated embodiment, along a vertical direction. This alternatingtranslational motion, during the rising motion, has no effect on therotation of the traction roller 5, whereas during the descending motionit causes the rotation of the traction roller 5 integrally with thepinions 17 a, 17 b that mesh with the corresponding rack 16 a, 16 b andconsequently causes by contact the rotation of the takeup roller 3 inthe winding direction 20. Due to the fact that the force that causes thedownward movement of the rack 16 a, 16 b is substantially constant, theforce transmitted by the traction roller 5 to the takeup roller 3 issubstantially constant and consequently the tensioning of the band 4during its winding about the takeup roller 3 is substantially constant.As a consequence of the progressive winding of the band 4 about thetakeup roller 3, the diameter of the assembly constituted by the takeuproller 3 and by the band 4 wound around it increases progressively, withconsequent rise of the traction roller 5 with its axial ends along thevertical guides 21 a, 21 b.

It should be noted that in the device according to the invention thetakeup roller 3 does not rest on the traction roller 5 and therefore itsprogressive increase in diameter and weight as the winding of the band 4progresses does not cause substantial variations of the force that istransmitted by the traction roller 5 to the takeup roller 3 andconsequently of the tensioning of the band 4, which therefore remainssubstantially constant during winding.

To avoid a rotation of the takeup roller 3 in the direction opposite tothe winding direction 20 in the step for loading the spring 23 a, 23 b,it is possible to interpose unidirectional rotation devices, such as forexample freewheel devices, also between the axial ends of the takeuproller 3 and the shoulders 8 a, 8 b that support them.

In practice it has been found that the device according to the inventionachieves fully the intended aim, since it ensures a substantiallyconstant tensioning of the band of fabric or knitting or the like duringits winding about the takeup roller, allowing uniform winding even withreduced tensions.

A further advantage of the device according to the invention is that itcan be actuated in a very simple manner and allows precise adjustment ofthe tension to which the band of fabric or knitting or the like issubjected during winding.

The device thus conceived is susceptible of numerous modifications andvariations, all of which are within the scope of the inventive concept;thus, for example, instead of providing two racks 16 a, 16 b it ispossible to provide a single rack.

All the details may further be replaced with other technicallyequivalent elements.

In practice, the materials used, as well as the dimensions, may be anyaccording to the requirements and the state of the art.

The disclosures in Italian Patent Application No. MI2012A001090 fromwhich this application claims priority are incorporated herein byreference.

1-11. (canceled)
 12. A winder for winding a band of fabric or knittingor the like on a roller, particularly for circular knitting machines,comprising a frame which supports, so that it can rotate about its ownhorizontally arranged axis, a takeup roller, on which the band of fabricor knitting or the like is to be wound, and at least one tractionroller, which is supported, so that it can rotate about its own axis,which is arranged in parallel to the axis of said takeup roller, by saidframe and can be actuated with a rotary motion about its own axis withrespect to said frame; said traction roller making contact with saidtakeup roller, with the interposition of said band wound around saidtakeup roller, for a transmission of the rotation of said tractionroller to said takeup roller, wherein said traction roller is arrangedso that its axis is above the axis of said takeup roller and can movetoward or away from the axis of said takeup roller as the windingdiameter of said band on said takeup roller varies, means being providedfor the actuation of said traction roller with a rotary motion about itsown axis with a substantially constant actuation torque.
 13. The deviceaccording to claim 12, wherein said actuation means comprise a rack,which is supported, so that it can slide, by said frame along adirection which is perpendicular to the axis of said traction roller,said rack meshing with a pinion connected to said traction roller bymeans of a unidirectional motion transmission device adapted to rendersaid pinion integral with said traction roller in rotation about its ownaxis in a forward rotation direction which actuates a rotation of saidtakeup roller in the direction of the winding of said band on saidtakeup roller and to uncouple said pinion from said traction roller in areturn direction of rotation which is opposite to said forward rotationdirection, said rack being actuated with a translational motion alongits own axis, at least in the direction of translation that causes saidforward rotation direction of said pinion, with a substantially constantforce.
 14. The device according to claim 12, wherein said actuationmeans comprise a rack which meshes with a pinion, which is connected tosaid traction roller by means of a corresponding unidirectional motiontransmission device for each one of the axial ends of said tractionroller.
 15. The device according to claim 14, wherein saidunidirectional motion transmission device is a device of the freewheeltype.
 16. The device according to claim 14, wherein said pinion isfitted coaxially on an axial end of said traction roller, saidunidirectional motion transmission device being interposed between saidtraction roller and said pinion.
 17. The device according to claim 12,wherein the axis of said traction roller and the axis of said takeuproller lie on a same vertical plane.
 18. The device according to claim12, wherein axial ends of said traction roller are accommodatedslidingly within vertical guides which are integral with said frame. 19.The device according to claim 14, wherein said rack is actuated with atranslational motion along its own axis, in the direction of translationthat causes said forward rotation direction of said pinion, by means ofa spring which is reloaded cyclically by a fluid-operated cylinder. 20.The device according to claim 14, wherein said rack is actuated with atranslational motion along its own axis, in the direction of translationthat causes said forward rotation direction of said pinion, by means ofa pneumatic spring which is embedded in a fluid-operated cylinder whichcan be actuated cyclically in order to reload said pneumatic spring. 21.The device according to claim 14, wherein said rack is actuated with analternating translational motion along its own axis by means of adouble-acting fluid-operated cylinder.
 22. The device according to claim19, further comprising means for adjusting an actuation force of saidrack at least in the direction of translation that causes said forwardrotation direction of said pinion.